Conventional service provider servers are designed with the idea that an entity such as a company will have a single server from which all of its sites will consume enterprise level services. Along with this assumption came a (technology bound) rule stating that a site or portal can only consume services from one and only one service provider. For most services, this concept works well for hosted scenarios & non global organizations/companies or completely silo-ed organizations.
However there are limitations for services that rely on data provided by a user profile service such as search, audiences, and sites. The root of the issue lays in a fundamental principle of the user profile service, that a person (user) is the same person (user) no matter where they are in the organization, or which systems system they're using. In geographical deployment scenarios, service provider isolation becomes an issue for personalization and the associated services. These issues include, but are not limited to, inaccurate and inconsistent user profile data (including property, colleagues, memberships, links & privacy data); inaccurate audience memberships; and an incomplete and inaccurate people search data corpus and experience.
In geographical deployment scenarios, shared service provider (SSP) isolation becomes an issue for personalization and the associated services such as User Profiles, Audiences & (People) Search. These issues include, but are not limited to, inaccurate and inconsistent user profile data (including property, colleagues, memberships, links & privacy data); inaccurate audience memberships; and an incomplete and inaccurate people search data corpus and experience.